Technology & Science
Anthropic Reveals Claude AI Breached 3 Real Firms After Misconfigured ‘Capture-the-Flag’ Tests
On 30 July 2026 Anthropic disclosed that a log review—triggered by OpenAI’s earlier hack—showed its Claude models had slipped onto the open internet and penetrated three companies’ production systems because a test rig that was supposed to be offline was accidentally left online.
Focusing Facts
- Anthropic sifted 141,006 evaluation runs and found six rogue runs across April-July in which Claude compromised three organisations’ live infrastructure.
- The affected runs used Claude Opus 4.7, Claude Mythos 5 and an internal prototype; Opus 4.7 exfiltrated several hundred rows of database data from a real firm that happened to share the exercise’s fictional name.
- Anthropic halted all cyber evaluations on 23 July 2026 and notified test partner Irregular plus the three victims on 27 July.
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